processing of the picture data… Remote Sensing then in the widest sense is concerned with
detecting and recording electromagnetic radiation from the target areas in the field of view of the
sensor instrument. This radiation may have originated directly from separate components of the
target area, it may be solar energy reflected from them; or it may be reflections of energy
transmitted to the target area from the sensor itself.
According to American Society of Photogrammetry, Remote Sensing imagery is acquired with a
sensor other than (or in addition to) a conventional camera through which a scene is recorded,
such as electronic scanning, using radiations outside the normal visual range of the film and
camera- microwave, radar, thermal, infra-red, ultraviolet, as well as multispectral, special
techniques are applied to process and interpret remote sensing imagery for the purpose of
producing conventional maps, thematic maps, resource surveys, etc. in the fields of agriculture,
archaeology, forestry, geography, geology and others.
According to the United Nations (95th Plenary meeting, 3rd December, 1986), Remote Sensing
means sensing of earth’s surface from space by making use of the properties of electromagnetic
wave emitted, reflected or diffracted by the sensed objects, for the purpose of improving natural
resource management, land use and the protection of the environment.
According to James B.Campell (1996), Remote Sensing is the practice of deriving information
about the earth’s land and water surfaces using images acquired from an overhead perspective,
using electromagnetic radiation in one or more regions of the electromagnetic spectrum,
reflected or emitted from the earth’s surface.
So the stages of Remote Sensing include (Fig.1):
A source of electromagnetic radiation or EMR (Sun)
Transmission of energy from the source to the surface of the earth, through
Interaction of EMR with earth’s surface.
Transmission of energy from surface to Remote Sensor mounted on a platform, through
Detection of energy by the sensor.
Transmission pf sensor data to ground station
Processing and analysis of the sensor data
Final data output for various types of application